In a background fuser unit that is used for an image forming apparatus, a fuser unit configured to fix a toner image on a sheet conveyed between a heating roller and a pressing belt has been known.
As the background fuser unit, a fuser unit includes a belt guide having a guide part configured to guide an inner surface of the pressing belt, a protrusion and an end-surface restraining part configured to contact an end surface of the pressing belt and a pressing arm disposed at an outer side of the belt guide in a first direction of the pressing belt.
Accordingly, when the pressing belt is deflected by circulating movement, an end surface of the pressing belt is contacted to the end-surface restraining part and the belt guide is enabled to swing at the protrusion serving as a support point, so that a force to be applied to the end-surface restraining part can be dispersed.